Public health round-up

Each country and territory using the trivalent oral polio vaccine (that protects against three types of the virus) should switch to the bivalent oral polio vaccine (that protects against two types of the virus) during the last two weeks of April next year, a group of experts has concluded. The Strategic Advisory Group of Experts on immunization (SAGE), which advises WHO, said that the 149 countries and seven territories using the oral polio vaccine should step up their efforts to prepare for the globally coordinated switch from trivalent oral polio vaccine to bivalent oral polio vaccine between 17 April and 1 May 2016. Within those two weeks, countries should remove all stocks of trivalent oral polio vaccine and confirm their removal to WHO, the experts said. Global withdrawal of the type 2 polio virus component in the oral polio vaccine is a crucial part of the polio endgame strategy: WHO’s plan to wipe out the disease. It is the first phase of the planned removal of all oral polio vaccines, with the type 1 and type 3 components of the vaccines to be removed after the global eradication of all wild poliovirus types has been certified. Withdrawing oral polio vaccine is crucial for eliminating very rare cases of vaccine associated paralytic polio (VAPP) or circulating vaccine derived polioviruses (cVDPVs). The type 2 component of oral polio vaccine accounts for 40% of VAPP cases, and more than 90% of cVDPV cases. By contrast, wild poliovirus type 2 has not been detected anywhere since 1999 and, in September, the Global Commission for the Certification of Poliomyelitis Eradication declared this strain globally eradicated. The SAGE cautioned, however, that more work needs to be done ahead of the April 2016 switch. A critical step is that the global community ensure poliovirus type 2 is appropriately contained so that it is not released into the environment, inadvertently or deliberately, to again cause paralysis or death in humans. To do this, each country should implement the measures that are outlined in the WHO global action plan for containing polioviruses that was endorsed by the ministries of health of all 194 WHO Member States in May. http://www.polioeradication.org/